1. Field of the Invention
The present invention generally relates to a magnetic head inspection method and a magnetic head inspection device for inspecting a thin film magnetic head as well as a magnetic head manufacturing method, in particular, to a magnetic head inspection method and a magnetic head inspection device capable of inspecting the track width of a thin film magnetic head that cannot be inspected by an optical microscope as well as a magnetic head manufacturing method.
2. Description of Related Art
In recent years, with the rapid increase of surface recording density of the hard disk drive (HDD), the write track width of a thin film magnetic head becomes miniaturized, and thus the importance of the technology of accurately inspecting a write track width written onto a magnetic disk by using a write pole (element) included in the thin film magnetic head continues to increase.
In the past, an optical microscope was employed to measure the shape of the write pole (element) included in the thin film magnetic head. However, with the miniaturization of the track width, the write track width reaches an optical system resolution limit or is narrower than the optical system resolution. Thus, it is difficult to use the optical microscope to measure the shape of the write pole (element). As a result, a scanning electron microscope (SEM) has been recently adopted to replace the optical microscope for measuring the shape of the write pole (element). However, the measurement performed by using the SEM is a kind of destructive inspection. Moreover, similar to the optical microscope, the SEM only measures the physical shape of the write pole (element), which results in the following problem. That is, it is difficult to measure the correlation with the effective magnetic track width (write track width) actually written onto the magnetic disk. In addition, even if the technology of using an atomic force microscope (AFM) to measure the shape of the write pole (element) is adopted, the same problem as described above may also exist. Recently, Japanese Patent Laid-Open Publication No. 2003-248911 has disclosed a magnetic head measuring device. The magnetic head measuring device is formed in a manner that the magnetic field characteristics, i.e., the magnetic field saturation phenomenon, of a write pole may be observed visually by using a magnetic force microscope (MFM).
When the shape of the magnetic head (write pole) is measured by using the SEM or AFM as in the past, though the physical shape of the write pole (element) can be measured, the effective magnetic track width (write track width) actually written onto the magnetic disk cannot be measured. Therefore, in the past, a head disk dedicated measuring device called a spin stand is employed to inspect the write track width in a state after the magnetic head is integrated with a suspension (i.e., a head-gimbal assembly (HGA) state) or in a simulated HGA state.
However, if the inspection with the spin stand is not performed in a final process of magnetic head manufacturing in an HGA state or a simulated HGA state, the inspection of the write track width cannot be implemented. Thus, the inspection with the spin stand is not ideal for improving the productivity or dealing with the requirement for an early feedback in the manufacturing process.